THE Black Gold that came from the sea. A review of Obsidian studies at the island of Ustica

Abstract

Volcanism has produced a natural glass called obsidian that during prehistoric times, from Neolithic to the Metal Ages, was considered a valuable raw material in order to produce efficient cutting tools. Ustica, a small and solitary island in the southwestern Tyrrhenian Sea, despite being volcanic, did not generate any obsidian. Yet the island's soils return large quantities of obsidian fragments, residues of prehistoric use. Where did this material, defined by some archaeologists as the Black Gold of prehistory, come from? This article reviews the archaeometric studies on Ustica’s obsidians, carried out since the middle of the 1990s, to answer this question. The obsidians of Ustica have become a tracer of commercial and cultural exchanges in the heart of the Mediterranean Sea. The geochemical fingerprint of Ustica obsidians is revealing a network of relations and exchanges not only with neighboring Lipari but also with the most distant Pantelleria and Palmarola islands. A fact that, for a tiny island that was completely devoid of spring water resources, appears surprising, in relation to the prehistoric context.